Next step - Not to let him back unless he comes back crawling, admits to his cheating and he has convinced you that he loves you, wants to be married and will never cheat again. Otherwise, you should do what you told him you are doing, and go about living your life (as best you can at this stage) because you don't want to be married to someone who is cheating on you.
Hang around waiting for him to decide that you are the one! What I say next is text book so here it is, if he loved you he would not have cheated and you would have been enough for him.
That man has just humilated you so IF you can turn your back on him and find someone who will treat you like they should then do that.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.